Encrypted Media: Use uint32 for systemCode in SessionError.

media/cdm/ppapi/external_clear_key/clear_key_cdm.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/cdm/ppapi/external_clear_key/clear_key_cdm.h"
 
 #include <algorithm>
 #include <cstring>
 #include <sstream>
 #include <string>
@@ skipping 574 matching lines @@
 
   host_->OnSessionReady(session_id);
 }
 
 void ClearKeyCdm::OnSessionClosed(uint32 session_id) {
   host_->OnSessionClosed(session_id);
 }
 
 void ClearKeyCdm::OnSessionError(uint32 session_id,
                                  media::MediaKeys::KeyError error_code,
-                                 int system_code) {
+                                 uint32 system_code) {
   host_->OnSessionError(
       session_id, static_cast<cdm::MediaKeyError>(error_code), system_code);
 }
 
 #if defined(CLEAR_KEY_CDM_USE_FAKE_AUDIO_DECODER)
 int64 ClearKeyCdm::CurrentTimeStampInMicroseconds() const {
   return output_timestamp_base_in_microseconds_ +
          base::Time::kMicrosecondsPerSecond *
          total_samples_generated_  / samples_per_second_;
 }
@@ skipping 59 matching lines @@
 
 void ClearKeyCdm::OnFileIOTestComplete(bool success) {
   DVLOG(1) << __FUNCTION__ << ": " << success;
   std::string message = GetFileIOTestResultMessage(success);
   host_->OnSessionMessage(
       last_session_id_, message.data(), message.size(), NULL, 0);
   file_io_test_runner_.reset();
 }
 
 }  // namespace media